Electric initiator for fuze



Feb. 28, 1961 R, H, STRESAU 2,972,951

ELECTRIC INITIATOR FOR FUZE Filed May 6, 1952 INVENTOR R. H. STRESAU ATTORNEYS ELECTRIC INITIATOR FOR FUZE Richard H. Stresau, Washington Grove, Md., assigner to the United States of America as represented by the Secretary of the Navy Filed May 6, 1952, Ser. No. 286,415

1 Claim. (Cl. U12-70.2)

(Granted under Title 3'5, U.S. Code (1952), sec. 266) The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

This invention relates to an explosive device and more particularly to an electroresponsive detonator for use in an ordnance missile.

The present invention contemplates the provision of a new and improved low energy detonator wherein the electric initiator therefor comprises a disc composed of paper or the like having a low energy bridge Wire secured thereto by means of a spray metal and vin which the spray metal provides means whereby an electrical impulse is transmitted to the bridge wire from an external source of energy whereupon the bridge wire will initiate an explosive charge arranged within the detonator casing in engagement with the charge. Furthermore, the present invention provides a low energy detonator which is cornpact in size, eicient in operation and possesses all'the qualities of ruggedness and durability during handling and transportation.

An object of the present invention is to provide a new` and improved electroresponsive detonator for use in an ordnance missile.

Another object of the invention is the provision of an electroresponsive detonator having a new and improved electric initiating unit for firing an explosive charge'n response to an electrical impulse received thereby. u

Another object of the invention is the provision of aV new and improved electrical initiating unit for a detonator having a low energy bridge wire secured thereto and redV in response to an electrical impulse received thereby for` firing an explosive charge and in which means connected to an external source of,electrica1 energy transmit the. iiring impulse to the bridge wire. I f' Still another object of the invention is the provision of an electrical intiating'unit for a detonator; wherein a length of iine initiating wire bonded thereto fires an explosive charge as "the, wire is heated toincandescence responsey to Vlran electrical impulse received t hereby.-

Other objects and many of `the attendant advantages of this invention will' be readily appreciated as the same becomesV better understood by reference to the following detailed descripionwhen considered ,in connection `with theacconipanying drawingrwhereinr.;`

Fig. l is an enlarged central longitudinal sectional View of the device of the present invention in accordance with a preferred embodiment thereof;

Fig. 2 is a cross sectional view taken on the line 2--2 of Fig..l;

Fig.v 3 is an enlarged sectional view of the initiating unit employed in the device of Fig. 1;

Fig. 4 is a view similar to Fig. l illustrating an alternative arrangement thereof;

Fig. 5 is a cross sectional view taken on `the line 5-5 of Fig. 4; and,

Fig- 6 is an enlarged sectional view of the initiatingl unit employed in the device of Fig. 4.

97,951 Patented Fein. 2S, 1961 Referring now to the drawing and more particularly to Fig. l thereof, the numeral 10 generally designates an electroresponsive detonator or primer comprising a casing 11 composed of any material suitable for the purpose such, for example, as copper or the like. Disposed within the casing 11 and secured thereto as at 12 is an inner container or supporting member 13, the inner container being spaced from the end wall 14 formed on the casing 11.

A sleeve 15 composed of any material suitable for the purpose such, for example, as steel or the like is arranged within the member 13, the sleeve being arranged between a ange 16 formed on one end of the member 13 and an initiating unit generally indicated by the numeral 17. The unit 17 is disposed within the member 13 in abutting engagement with the sleeve 15 and maintained in abutting engagement therewith by a flange 18 formed thereon and crimped into engagement with the unit as clearly shown on Fig. 1.

The initiating unit comprises a pair of discs 19 and 21 composed of any suitable insulating material such, for example, aspaper, rubber or the like, the disc 19 being arranged adjacent the sleeve 15 in abutting engagement therewith, the disc 21 being arranged adjacent the ange 18 in abutting engagement therewith. A terminal plate 22 is arranged between the discs 19 and 21 and in abutting engagement with the disc 21. The plate 22 has formed thereon a terminall 23, the terminal being arranged in a centrally. disposed opening 24 formed in the disc 21 and extending a predetermined amount therebeyond. By this arrangement an external source of electrical energy may be connected to the terminal 23.

A centrally disposed electrode generally indicated by the numeral 25 is secured to the disc 19 and comprises a contact member 26 formed thereon and in engagement with the plate 22. Formed on the member 26 and disposed n a centrally arranged aperture 27 formed in the disc 19 is a reduced extension or lug 2S having formed thereon a head 29 of greater diameter than the extension 28. As shown more clearly on Figs; 2 and 3V the head 29 is disposedwithin an elongated recess or depression 20 formedV in the disc 19 and thus by this ar-V rangement the outer surface of the head is flush with the corresponding surface of the disc 19. .A contact l3:1 is disposed within the recess 20 adjacent the head 29 and in spaced relation with respect there- As more clearly shown on Fig. 3 a length of fine initiating wire 32 is secured to the aforesaid elements 29 and 31 and bridges the space therebetween as at 30. lThe elements 25 and 31'are composed of any material suitable for the purpose such,rfor example, as silver,

silver solder, copper or the like, the aforesaid elements being'applied to the opposite sides of the disc 19 in any suitable' manner. The elements 26 and 29 are preferably applied by suitablymasking the faces of the disc 19 and sprayingfthereon a molten metal whereby the elements 26 and 29 are secured to disc 19 and are integrally united as at k28. Itwill beunderstood that when Vthe spraying operation has beenfcompleted, the free ends of the wire are encased in the members 29 and 331 with the minute bridge portion 30 thereof exposed. Furthermore, the initiating wire may be composed of any metal suitable vfor the purpose such, for example, as tungsten or niwire is heated to incandescence. The firing impulse to Ythe initiating wire 32 is established from a suitable source of electrical energy by way of terminal 23, plate 22, electrode 25, through the bridge wire 32 and thence t0 contact 31, which is grounded to the casingsby way of sleeve 15.

The detonator of Fig. 4 is similar`to the device ofY Fig. 1 and comp-rises a casing 34 closed on one end as by a wall 35, the other end thereof having a ilange 36 formed thereon. Disposed within the casing 34 is a cupshaped member 37 composed of suitable insulating material such, for example, as any of the phenolic plastic materials, the member 37 being maintained within the casing 34 by the aforesaid flange 36 which is crimped into engagement with the member 37 as at 3 8. 1

A sleeve 39 composed of steel o-r the like is arranged within the member 37, the sleeve having a ange 41 formed thereon in engagement with the member 37. By this arrangement the sleeve is supported within the member 37. c y c A substantially cone shaped member 42. is arranged with the conical portion 43 of the member 37, the member 42 having formed thereon a terminali 44. disposed within a centrally disposed aperture 45 formed in the conical portion 43 and extending a predetermined` amount therebeyond. v

An initiating unit generally indicated by the reference character 46 is arranged between the conical member 42 and sleeve 39, the unit comprising a disc 47 composed of suitable insulating material such, for example, as heavy paper or. any of the phenolic plastic materials. Securedy to the disc 47 is a pair .of conducting plates 48 and 49 composed o-f silver or the like and sprayed thereon in a molten condition, the plate 48 being in engagement with the metalV sleeve 39 and the plate 49L being in'engagement with the member 42. The unit is provided with a cen-V trally disposed'opening 51 extending `therethrough. Ar ranged within the opening 51 and Yhaving thecfree ends 52 and 53 encased in the plates 48 V`and 49 respectively is aninitiating element 54 composed of a length, of ne wire similar to the type ofwire employed with the device of Fig. l. It will be understood that during thefsprayf ing operation the free ends 52 andl 53 of the initiating Wire 54 are securely encased in the plates 48 and 49 as the molten metal is sprayed onto the disc 47.`

An explosive charge 55 is' arranged within the casing Magnetic Inertia Controlled Fuze, Serial No. 535,799, led May 16, 1944, now Patent No. 2,848,948. 'Furthermore, the. aforesaid arrangement may be employed for ring a battery of explosive charges simultaneously by arranging a detonator in each one of the battery charges and connecting them to a suitable sourcev of energy, it being obvious, however, that since one of the detonators is heated to incandescence by substantially 50 ergs all the detonatorswill be readily fired in responseto a relatively low amount of energy received thereby.

' From the foregoing descriptionl it will bereadily apparent that a new and improved detonator and initiating unit therefor is provided wherein a'ne initiating wire is secured to the surface of a disc composed of suitable insulating material, the effective length of the Wire being controlled by the application of molten metal to a portion of the disc and wire and thus by reasonrof the minute size ofthe wire and the small bridge portion thereof the wire may be heated to incandescence in response to a momentary application of a very low electrical impulse received thereby, the spray metal being instrumental in providing means whereby an electrical impulse is passed through the bridge Wire.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is thereforecto be understood that within the scope of the appended claim the invention may be practiced other thanV as specifically described.

What is claimed as new and desired to be secured b Letters Patent in lthe United States is: An electroresponsive detonator comprising a conductive casing having a flanged open end formed thereon, an ex* plosive charge arranged within said casing, acentrally apertured basek plate composed of insulating material seated upon said anged open end, an apertured disc composed of insulating material arranged within saidy casing, a pair of conductive surfaces sprayed on the top face of said disc while in a molten state, one ofV said surfaces encompassing the aperture in said disc, a bridge wire extending between and bonded to said conductive surfaces, a conductive llm sprayed on the under face of said disc while in a molten state and communicating with said onesurfacecthrough said disc aperture, a conductive disc engagingly positioned between saidconductive lrn and 34 and sleeve 39, the charge also filling the opening 151- formed in the unit 46 whereupon the initiating wirejis number of selected points simultaneouslyvbyemployingk a plurality of the detonators or primers placedalong the length of the charge at predetermined spaced intervals and connected in series in such a manner-as to operate in response to aV momentary applicationofa loworderf 1' 1 of electrical energy from a suitable source SUCh, for example, as a normally charged condenser 01" a-voltagegenerating device similar to the type disclosed-and claimedin the copending application of Harold J. lPlurnley for ignition of said explosive charge.

References Cited in tliejiile-of this patent Y UNITED STATES PATENTS lrance a 12111.31, 1951 

